1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to decoding methods and apparatuses in wireless communication devices.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division—Code Division Multiple Access (TD-CDMA), and Time Division—Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks. As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
Furthermore, in UMTS networks, wireless devices, or “user equipment” (UE), communicate with the network by transmitting information to, and receiving information from, UMTS network devices. Specifically, this information is organized into at least one transport block (TB) at the transmitting device, and the transport blocks are then separated into at least one code block (CB) for transmission. Each of these code blocks are separately turbo encoded and all turbo-encoded code blocks are transmitted to the receiving device—be it a UE or a network entity—in one subframe.
Upon receipt of the CBs, the receiving device places each of the code blocks into a receiver queue and decodes each of the code blocks that comprise the transport block individually. However, each of the code blocks do not contain cyclic redundancy check (CRC) information corresponding to the code block itself or the transport block of which it is a part. Instead, the CRC information is typically appended to one (or only a few) of the code blocks of a transport block. Thus, in legacy systems, to decode a full transport block with multiple code blocks and perform a CRC to ensure that the transport block has been successfully received, the receiving device must implement a brute-force approach to decoding and CRC procedures. This brute force implementation may require that a turbo decoder at the receiver decode each of the code blocks in the transport block multiple times (also referred to as “at full iterations”), such as, for example, during one or more decoding iterations that may occur at one or more of a first transmission of the transport block and any possible retransmission of the transport block.
Thereafter, once all the code blocks have been decoded, a CRC on the entire transport block may be performed to determine whether the entire transport block was correctly received. Such a procedure, however, consumes unnecessary time and energy because if one decoded code block contains any incorrect bits, the entire transport block will fail the CRC even if all of the other decoded code blocks of the transport block are correct.
Thus, methods and apparatuses for efficient transport and code block decoding at a receiving wireless device are needed.